The catalytic effect of Al-KIT-5 and KIT-5-SO₃H on the conversion of fructose to 5-hydroxymethylfurfural

The aim of this work is to study the production of hydroxymethylfurfural (HMF) from fructose using heterogenous catalysts based on KIT-5. For this propose, Al-KIT-5 and KIT-5-SO₃H as the Lewis and Bronsted catalysts were prepared and were characterized using different techniques such as FT-IR, SEM, EDS, TEM, BET, TGA and elemental analysis. With the use of Al-KIT-5 as the catalyst, the appropriate reaction temperature and time were 135 °C and 60 min, respectively. Moreover, with the use of KIT-5-SO₃H as the catalyst, the proper reaction conditions were found to be 125 °C and 45 min, respectively. In addition, the corresponding amounts of catalyst weight were 40 and 50 mg for KIT-5-SO₃H and Al-KIT-5, respectively. Under these conditions, the conversion of fructose was 93.9 and 88.3%, respectively. These results indicated that, due to its Bronsted acid nature, the KIT-5-SO₃H catalyst showed better results when 40 mg catalyst was used at 125 °C for 45 min in DMSO as the solvent. Both catalysts could be recycled and reused several times.